The present inventions relates, in general, to animal feeders, and more particularly, to animal-operated feeders which include a latch assembly and a latch release element worn by the animal, usually around its neck.
Various types of animal feeders have been developed which can be automatically operated by the animals on an as-needed basis. One approach which is commonly employed is the treadle operated animal feeder. Typical of such treadle-type animal feeders are the devices of U.S. Pat. Nos. 3,121,419, 3,301,219, 3,575,141 and 3,758,348. In these devices a barrier such as a lid, door, gate or panel is movably mounted to a housing or enclosure in which feed for the animal is positioned. A treadle or platform is coupled to the movable barrier and is positioned in front of the feed opening so that as the animal approaches the feed opening it must step on the treadle and thereby move the barrier.
These treadle-based devices have certain inherent disadvantages. First, they sometimes require relatively involved mechanisms. Additionally, the movement of the treadle under the animal's feet can scare the animal away from the feeder. Moreover, the feeders of the above prior-art do not provide any means for discriminating between animals. Thus, two animals of substantially the same size can operate the feeder, even though the feed may not be intended for one of the animals.
A second approach to animal-operated feeders can be found in U.S. Pat. Nos. 3,541,995, 3,557,757, 3,850,145, 4,036,178 and 4,162,683. All of these patents address the problems of selective feeding, so that only authorized or selected animals are able to operate the feeder, or demand feeding, so that excess feed is not available to other animals. For household pets, for example, the owner will want to feed only his or her animals, not the animals next door. Similarly for cattle and large animals, some animals may need one kind of feed and/or medication in the feed, while others feed on a different regimen. In both domestic and farm applications the animal owners do not want excessive feed available after the animal finishes eating. The feeders of these patents, therefore, provide the animals with a key or switch actuating device which will turn on a feed conveyor when the animal positions the key proximate to the switch at the feeder. A variety of magnetic and radio frequency actuated switch devices have been employed in the feeders.
Animal feeders which are based on conveyors and an animal carried switch actuator also have been found to have certain disadvantages. First, the switching on and off and operation of the conveyor can scare the animals. Secondly, some of the systems require complex electronic apparatus. Additionally, most of these systems require an electrical power source, which is not always feasible to provide and will result in failure to feed the animal if there is a power failure.
Finally, animal-operated animal feeders have also included feeders in which the animal carries a key which will unlatch a barrier or gate to permit the animal to have access to food in the feeder. Typical of such prior-art devices are the animal feeders of U.S. Pat. Nos. 3,180,321, 4,036,178 and 4,188,912.
In U.S. Pat. No. 3,180,321 a battery operated oscillator mounted around the animals neck can be used to actuate a radio receiver at the feed structure so that a gate powered by an electric motor is raised to permit the animal to have access to the feed. This structure has the disadvantages of cost, possible power failure and inherent complexity.
The animal feeder of U.S. Pat. No. 4,036,178 includes a transponder attached to the animal which is passive and replys to an interrogator to either operate a latch or dispense food. Again, this is an electrically powered solution which is relatively complex and inherently costly.
In the U.S. Pat. No. 4,188,912 a solonoid operated latch is provided which is actuated by a proximity switch that will be closed by a metal chain, or the like, worn by the animal. While the problem of conveyor noise has been eliminated by this releasable gate structure, it again must be battery powered with inherent potential for power failure, which could be disastrous if the feeder is used in remote or unsupervised locations. Additionally, the barrier gate which is moved by the animal is pushed inwardly of the feeder housing, and the feed inside the housing can interfere with the operation of the gate.